Conventionally, a sprinkling apparatus is used in bread-production systems in which bread dough is moved by a conveyor. The sprinkling apparatus is typically located above the conveyor, and includes a hopper for holding powder material such as flour, and a sprinkler for sprinkling the flour from the hopper onto the conveyed bread dough. For the best performance of the sprinkling apparatus, the sprinkler must stir the flour in the hopper so that the distribution of the sprinkled flour across or around the bread dough is reasonably uniform.
Various sprinkler apparatuses have been employed in bread-production systems. Two exemplary sprinkler apparatuses are disclosed on pages 67 and 68 of the Gazette of Collected and Widely and Commonly Used Techniques, which was published by the Japanese Patent Office on Feb. 20, 1980. The first sprinkler apparatus disclosed in the Gazette includes two parallel and connected rotating rollers mounted on a bottom opening of a hopper. One of the two rollers is a feeder roller in which slots are knurled on its rotating (peripheral) surface, and the other roller is a rotating brush. When the two rollers rotate, the feeder stirs the powder material in the hopper. The flour tends to stick to the rotating surface of the feeder, and is then brushed by the rotating brush. In the second sprinkler apparatus disclosed in the Gazette, a bottom portion of the hopper is formed from a net which is rubbed by a brush or plate mounted within the hopper so as to be reciprocally rotatable. When the meshed bottom portion of the hopper and the brush or plate are rubbed together, the powder material falls out of the hopper.
In the first sprinkler apparatus mentioned in the Gazette, sometimes the powder material is fine-grained, and tends to set, such as weak flour, and bridging of the flour can occur within the hopper so that the flour jams within it. The jammed flour causes the supply of flour to be insufficient and flour tends to be poorly sprinkled on the bread dough. Additionally, the sticking force for causing the flour to stick to the knurled slots of the feeder may be insufficient so that the flour falls off before reaching the rotating brush. Thus, there is a limit to the kinds of powder material that can be used for this type of sprinkler. Further, every brush stroke by the rotating brush stirs up the powder material, and causes the working environment to be contaminated.
A problem that arises with the second sprinkler apparatus of the Gazette is that the amount of powder material to be sprinkled changes rapidly before and after every passage of the brush or plate, thereby producing non-uniform sprinkling by the sprinkler apparatus. Thus, the powder material is distributed on the food product in a wave-like disproportionate pattern, and does not provide a suitably uniform distribution.